I have a unique problem that I have taken to a couple mechanics and they can't figure it out. It is kind of hard to explain, so I'll break it down step by step.

1. Start my truck when the engine is cold. (in the morning or after sitting all day during work.)
2. Turn on the heat and turn the blower on as high as it goes
3. The temperature gauge will go to what it usually runs at when everything is normal, but I'm still blowing out cold air.
4. The temperature gauge will start climbing to out 75 to 90%, and sometimes it will peg out and the Check Gauge light will come on. Sometimes I can smell antifreeze.
5. After about 5 to 10 seconds the temp. gauge will drop down to normal, and the heater will start blowing warm air. After this happens the everything runs perfectly fine. I even took it on a 3 hour road trip without any issues.

This is on a 2004 Expedition with 102K miles on it. I have had two thermostats put in and the cooling system flushed out twice. No one seams to know what is going on.

I'm hoping for a simple solution, but I'm not holding my breath.

Thanks for you help.

 

Just speculating.....

1. you've got a leak somewhere in the system....look at the t's in the heater lines....

2. air lock in system...

3. head gasket....verify through compression or pressurizing cooling system also look at oil....

 

I would get a hydrocarbon test performed to verify if you have a blown head gasket. Sounds like thats what it is to me. The blown gasket allows hot combustion gases from the affected cyl to enter the cooling system. You get a large bubble from those gases in the system and when that bubble reaches the temperature sensor it spikes the guage, bubble moves and temp guage drops. The coolant you smell is probably from the degas bottle releasing that pressure that is buildng in the system.

 

I was hopping it wasn't a head gasket, but I have a feeling that is what the problem is. Does anyone have a ballpark on what that costs? and how long do I have until it blows and absolutely have to get it fixed?

 

The sooner the better.....

 

Around $1K for head gaskets should be expected $1500 being tops. You'll know when it needs to get fixed when your stranded on the side of the road...just food for thought.A wise sage once said.

 

FYI I had EXACTLY the same issue you are describing at one point and it was a head gasket. Sucks I know :/